Iran-U.S.-Saudi tensions: The story so far, from the oil-field attacks to the nuclear deal

The latest

• Last weekend’s attack on the heart of Saudi Arabia’s oil industry was “unquestionably sponsored by Iran,” Riyadh alleged Wednesday, presenting remnants of drones and missiles it said were used in the attack. The Saudis named but not directly accuse Tehran of launching the strikes, while Iran denies being involved in the attack claimed by Yemeni rebels.
• U.S. President Donald Trump on Wednesday ordered a major increase in sanctions on Iran, which has threatened the United States that it will retaliate “immediately” if it is targeted in response to the Saudi attacks. Mr. Trump gave no explanation in a Twitter post announcing the order, but it followed repeated U.S. assertions that the Islamic Republic was behind Saturday’s attack.
• Yemen’s Iran-aligned Houthi group has claimed responsibility, and on Wednesday gave more details of the raid, saying it was launched from three sites in Yemen. In a remark that may further strain an already tense political atmosphere in the Gulf, the Houthis also said they had dozens of sites in the United Arab Emirates, Riyadh’s top Arab ally, listed as possible targets for attacks.
• The attacks on the Abqaiq plant and Khurais oil field have interrupted as many as 5.7 million barrels of Saudi crude oil production per day, equivalent to more than 5 per cent of the world’s daily supply. National oil firm Saudi Aramco is pressing ahead with plans for a local initial public offering this week, although some investors and analysts doubt Aramco can now meet its timeline as it has not said when oil output will be restored.

The Saudi oil-field attacks

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On Sept. 14, Saudi Arabia’s Abqaiq oil processing plant and its Khurais oil field were bombed by drones. The U.S. government produced satellite photos showing what officials said were at least 19 points of impact at the two Saudi energy facilities. Officials said the photos show impacts consistent with the attack coming from the direction of Iran or Iraq, rather than from Yemen, where Iranian-backed Houthi rebels claimed responsibility for the attack. On Sept. 17, the Saudis presented drone and missile debris they said was “undeniable” proof of Iranian involvement. Iran denied the allegations.

The attack halted production of 5.7 million barrels of crude a day, more than half of Saudi Arabia’s global daily exports. That would make it the greatest oil-supply disruption on record for world markets, according to figures from the Paris-based International Energy Agency. It just edges out the 5.6 million-barrels-a-day disruption around the time of Iran’s 1979 Islamic Revolution, according to the IEA.

Backstory: How the feud escalated over the summer

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It’s been more than a year since Mr. Trump pulled the United States out of a 2015 nuclear deal with Iran. Since then, Tehran and Washington have been in a heated diplomatic and economic feud. It inched closer to actual war this past spring, when the Iranians threatened to start up uranium enrichment again and the Americans deployed a carrier strike group and Patriot missile battery into the Middle East.

Two attacks against commercial shipping in the Gulf of Oman escalated the conflict further: One on May 12, when four ships (including oil tankers belonging to Saudi Arabia, a U.S. ally) were hit by “sabotage operations” off the United Arab Emirates coast, and again on June 13, when two oil tankers were attacked near the Strait of Hormuz. Both times, the Trump administration blamed Iran; both times, Iran denied it.

Then on June 17, Iran said it would break the nuclear deal and exceed its uranium limit unless the remaining signatories did something to save the deal by July 8. Soon after, the Pentagon announced 1,000 more troops would be deployed to the Middle East. Those troops came close to attacking Iranian targets on June 20, when Iran’s Revolutionary Guard shot down a U.S. surveillance drone that they said was in Iranian airspace in the southern province of Hormozgan, but that the U.S. military said was in international airspace over the Strait of Hormuz. Mr. Trump authorized retaliatory strikes, but said he changed his mind 10 minutes before they were due to be launched.

The nuclear deal explained

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Iran’s current standoff with the West centres on a deal brokered by U.S. president Barack Obama between Iran and six world powers – Britain, China, France, Germany, Russia and the United States – designed to curb Iran’s possible future development of nuclear weapons. In exchange, the signatories would lift sanctions that had been crippling the Iranian economy. But after the Trump administration brought back sanctions on Iran, the nation’s government threatened to start up enrichment again. Here’s what that means.

What is uranium enrichment? Turning uranium ore into nuclear fuel is an elaborate process, and the UN atomic energy agency has strict rules about who can perform what step. First, ore is crushed and treated with acids to produce a powder of concentrated uranium oxide called yellowcake. Only about 0.7 per cent of this is uranium-235, the isotope that reactors need to produce fission power. To get that percentage up, the uranium is turned into a gas, uranium hexafluoride, and put through one of two processes to sort the U-235 from the more common and heavier isotopes: The diffusion method, which forces the gas through membranes, or the centrifugal method, which spin the gas very fast through a chain of hundreds or thousands of centrifuges so the lighter U-235 can be siphoned off.

Uranium enrichment

Natural uranium consists of less than 1% of the U-235 isotope needed for fission chain reaction. For a nuclear power plant, uranium must be enriched in a centrifuge to relatively low levels of purity. Further enriched, it can be used in a nuclear weapon.

How centrifuges work

1

5

2

Casing

Cylinder

4

3

Motor

Uranium hexafluoride gas fed into the rotating cylinder and spun at high speed

1

Gas slightly depleted of U-235 is fed back to previous stages

2

Heavier U-238 molecules collect on outside of cylinder.

3

Lighter U-235 molecules collect closer to centre of cylinder.

4

Gas slightly enriched in U-235 is fed to the next stage.

5

Cascades

The process is repeated through hundreds or thousands of centrifuges, known as a cascade, until a gas that is highly enriched in U-235 is created.

Highly enriched U-235 gas

After the first enrichment, the uranium will be

about 3.5% U-235 isotope

3.5%

20%

60%

90%

SOURCE: REUTERS

Uranium enrichment

Natural uranium consists of less than 1% of the U-235 isotope needed for fission chain reaction. For a nuclear power plant, uranium must be enriched in a centrifuge to relatively low levels of purity. Further enriched, it can be used in a nuclear weapon.

How centrifuges work

1

5

2

Casing

Cylinder

4

3

Motor

Uranium hexafluoride gas fed into the rotating cylinder and spun at high speed

1

Gas slightly depleted of U-235 is fed back to previous stages

2

Heavier U-238 molecules collect on outside of cylinder.

3

Lighter U-235 molecules collect closer to centre of cylinder.

4

Gas slightly enriched in U-235 is fed to the next stage.

5

Cascades

The process is repeated through hundreds or thousands of centrifuges, known as a cascade, until a gas that is highly enriched in U-235 is created.

Highly enriched U-235 gas

After the first enrichment, the uranium will be about 3.5%

U-235 isotope

3.5%

20%

60%

90%

SOURCE: REUTERS

Uranium enrichment

Natural uranium consists of less than 1% of the U-235 isotope needed for fission chain reaction. For a nuclear power plant, uranium must be enriched in a centrifuge to relatively low levels of purity. Further enriched, it can be used in a nuclear weapon.

How centrifuges work

Uranium hexafluoride gas fed into the rotating cylinder and spun at high speed

Gas slightly depleted of U-235 is fed back to previous stages

Gas slightly enriched in U-235 is fed to the next stage.

Casing

Heavier U-238 molecules collect on outside of cylinder.

Lighter U-235 molecules collect closer to centre of cylinder.

Cylinder

Motor

Cascades

The process is repeated through hundreds or thousands of centrifuges, known as a cascade, until a gas that is highly enriched in U-235 is created.

Highly enriched U-235 gas

After the first enrichment, the uranium will be about 3.5% U-235 isotope

3.5%

20%

60%

90%

SOURCE: REUTERS

Why do the percentages matter? If the concentration of U-235 is lower than 20 per cent, it’s called low-enriched uranium: Anything above that is high-enriched. Nuclear reactors need a U-235 concentration of only 3 to 5 per cent, but the material needed for nuclear bombs, or “weapons-grade” uranium, generally has to be 90 per cent or higher. Before the 2015 deal, Iran could enrich uranium to about 20 per cent: Too low for a weapons program, but high enough to worry Western powers that Iran was headed in that direction.

How much enriched uranium can Iran have? Under the 2015 deal, Iran could have no more than 300 kilograms of low-enriched uranium stockpiled for 15 years, and the enrichment could go no higher than 3.67 per cent. On July 7, Iran announced it had passed that threshold by making 4.5 per cent enriched uranium, and threatened to restart deactivated centrifuges that could make up to 20 per cent.

Why is the deal in trouble? The U.S. Congress gave the president power to review every 90 days whether Iran was complying with the deal. U.S. President Donald Trump, who campaigned openly against a deal he said was the “worst ever,” came to office in 2016 and renewed Iran’s certification twice before finally pulling out in May, 2018, restarting sanctions a few months later. The European signatories still support the deal, but have so far not delivered on promises to shield Iran from the economic impact of U.S. sanctions.

THE NUCLEAR DEAL'S DOWNFALL

U.S. President Donald Trump reimposed sanctions on Iran in November of 2018. Here is the backstory behind that

Uranium mines

Reactor

Uranium enrichment

Military

Fordow: Under deal, fuel enrichment halted for 15 years. Facility converted for medical isotope research only

1

Arak: Heavy water reactor redesigned to prevent production of weapons-grade plutonium

2

Centrifuges at Natanz and Fordow cut from 20,172 to 6,104. Uranium enrichment limited to 3.67%

3

0

400

Caspian Sea

KM

Ramsar

IRAN

Bonab

Tehran

1

3

Karaj

Parchin

2

Natanz

Isfahan

Saghand

IRAQ

Ardakan

IAEA* to monitor uranium mining for 25 years

Bushehr

Gachin

Persian

Gulf

SAUDI ARABIA

2013: Hassan Rouhani

(left) elected Iran’s

president, replacing

hard-line Mahmoud

Ahmadinejad

Nov. 2013: Iran agrees to

pact withU.S., Britain, China,

France,Germany and Russia

to curbnuclear work in return

for sanctions relief

Jan 2016: Iran nuclear deal – JCPOA** – enacted. Iran receives $100-billion of its assets frozen in foreign banks

2015: Congress passes Iran Nuclear Agreement Review Act – INARA – which allows U.S. President to reimpose sanctions

Sep 2017: IAEA says Iran

is in compliance with JCPOA.

U.S. and EU say missile tests

violate UN resolution 2231

which is part of deal

May 8, 2018:

Trump announces

U.S. pulling

out of Iran

nuclear deal

*International Atomic Energy Agency

**Joint Comprehensive Plan of Action

THE GLOBE AND MAIL, SOURCE: GRAPHIC NEWS

THE NUCLEAR DEAL'S DOWNFALL

U.S. President Donald Trump reimposed sanctions on Iran in November of 2018. Here is the backstory behind that

Uranium mines

Reactor

Military

Uranium enrichment

Fordow: Under deal, fuel enrichment halted for 15 years. Facility converted for medical isotope research only

1

Arak: Heavy water reactor redesigned to prevent production of weapons-grade plutonium

2

Centrifuges at Natanz and Fordow cut from 20,172 to 6,104. Uranium enrichment limited to 3.67%

3

0

400

TURKEY

Caspian Sea

KM

Ramsar

IRAN

Bonab

Tehran

1

3

Karaj

Parchin

2

Natanz

Isfahan

IRAQ

Saghand

Ardakan

IAEA* to monitor uranium mining for 25 years

Bushehr

Gachin

Persian

Gulf

SAUDI ARABIA

2013: Hassan Rouhani

(left) elected Iran’s

president, replacing

hard-line Mahmoud

Ahmadinejad

Nov. 2013: Iran agrees to pact

with U.S., Britain, China, France,

Germany and Russia to curb

nuclear work in return for

sanctions relief

Jan 2016: Iran nuclear deal – JCPOA** – enacted. Iran receives $100-billion of its assets frozen in foreign banks

2015: Congress passes Iran Nuclear Agreement Review Act – INARA – which allows U.S. President to reimpose sanctions

Sept. 2017: IAEA says Iran

is in compliance with JCPOA.

U.S. and EU say missile tests

violate UN resolution 2231

which is part of deal

May 8, 2018:

Trump announces

U.S. pulling

out of Iran

nuclear deal

*International Atomic Energy Agency

**Joint Comprehensive Plan of Action

THE GLOBE AND MAIL, SOURCE: GRAPHIC NEWS

THE NUCLEAR DEAL'S DOWNFALL

U.S. President Donald Trump reimposed sanctions on Iran in November of 2018. Here is the backstory behind that

Uranium mines

Uranium enrichment

Military

Reactor

TURKEY

Caspian Sea

Ramsar

Centrifuges at Natanz and Fordow cut from 20,172 to 6,104. Uranium enrichment limited to 3.67%

Fordow: Under deal, fuel enrichment halted for 15 years. Facility converted for medical isotope research only

Bonab

Tehran

Karaj

Parchin

IRAN

Natanz

IRAQ

Isfahan

Saghand

Arak: Heavy Water Reactor redesigned to prevent production of weapons-grade plutonium

Ardakan

IAEA* to monitor uranium mining for 25 years

Bushehr

Gachin

Persian

Gulf

0

400

SAUDI ARABIA

KM

2013: Hassan Rouhani

(left) elected Iran’s

president, replacing

hard-line Mahmoud

Ahmadinejad

Nov. 2013: Iran agrees to pact with

U.S., Britain, China, France,

Germany and Russia to curb

nuclear work in return for

sanctions relief

Jan 2016: Iran nuclear

deal – JCPOA** – enacted.

Iran receives $100-billion

of its assets frozen in

foreign banks

2015: Congress passes

Iran Nuclear Agreement

Review Act – INARA –

which allows U.S. President

to reimpose sanctions

Sept. 2017: IAEA says Iran

is in compliance with JCPOA.

U.S. and EU say missile tests

violate UN resolution 2231

which is part of deal

May 8, 2018:

Trump announces

U.S. pulling

out of Iran

nuclear deal

*International Atomic Energy Agency **Joint Comprehensive Plan of Action

THE GLOBE AND MAIL, SOURCE: GRAPHIC NEWS

Bad blood: The bigger implications of an Iran-U.S. feud

Iran vs. Saudi Arabia

The Middle East is split into two camps along political and religious lines: On one side is Saudi Arabia, which adheres to a hard-line version of Sunni Islam, and on the other is Shia Iran. Proxy conflicts between the blocs, such as the civil war in Yemen between Iran-aligned Houthi rebels and a Saudi-aligned national government, have taken an increasingly deadly toll in recent years. The September attacks on Saudi oil facilities have raised fears of open warfare between Iran and a Saudi Arabia backed by U.S. military might.

The Strait of Hormuz

Open this photo in gallery:

The Strait of Hormuz, which links the Persian Gulf to the Gulf of Oman and the open ocean, is a narrow corridor through which nearly 40 per cent of the world’s crude oil passes – and Iran lies right alongside it. Iran has mined the strait before or threatened to close it entirely in times of crisis, such as its 1980-88 war with Iraq and the standoff over nuclear sanctions in the early 2010s. But the U.S. Navy, whose Fifth Fleet is based in Bahrain, has been in sometimes tense standoffs with Iran to ensure the strait stays open to shipping.

Petroleum transit volumes through

seven major chokepoints, 2016

Millions of barrels per day

1

Strait of Hormuz

18.5

2

Strait of Malacca

16

Suez Canal and

SUMED pipeline

3

5.5

Bab el-Mandeb

strait

4

4.8

5

Danish straits

3.2

6

Turkish straits

2.4

7

Panama Canal

0.9

1

2

3

4

5

IRAN

6

Atlantic

Ocean

7

Indian

Ocean

0

1,500

KM

IRAN

0

70

KM

Strait of

Hormuz

OMAN

Persian Gulf

Dubai

Gulf of Oman

UAE

OMAN

MURAT YÜKSELIR / THE GLOBE AND MAIL, SOURCE:

TILEZEN; OPENSTREETMAP CONTRIBUTORS;

HIU; EIA.GOV

Petroleum transit volumes through

seven major chokepoints, 2016

Millions of barrels per day

1

Strait of Hormuz

18.5

2

Strait of Malacca

16

Suez Canal and

SUMED pipeline

3

5.5

Bab el-Mandeb

strait

4

4.8

5

Danish straits

3.2

6

Turkish straits

2.4

7

Panama Canal

0.9

1

2

3

4

5

IRAN

6

Atlantic

Ocean

7

Indian

Ocean

0

1,500

KM

IRAN

0

70

KM

Strait of

Hormuz

OMAN

Persian Gulf

Dubai

Gulf of Oman

UAE

OMAN

MURAT YÜKSELIR / THE GLOBE AND MAIL, SOURCE: TILEZEN;

OPENSTREETMAP CONTRIBUTORS; HIU; EIA.GOV

Petroleum transit volumes through seven major chokepoints, 2016

Millions of barrels per day

Panama

Canal

Danish

straits

Turkish

straits

Suez Canal

and SUMED

pipeline

Bab el-

Mandeb

strait

Strait of

Hormuz

Strait of

Malacca

0.9

3.2

2.4

5.5

4.8

18.5

16

IRAN

Atlantic

Ocean

Pacific Ocean

0

70

IRAN

Indian

Ocean

KM

Strait of

Hormuz

OMAN

Persian Gulf

Dubai

Gulf of Oman

0

1,500

UAE

OMAN

KM

MURAT YÜKSELIR / THE GLOBE AND MAIL, SOURCE: TILEZEN; OPENSTREETMAP

CONTRIBUTORS; HIU; EIA.GOV

Commentary and analysis

Bessma Momani: After Saudi oil attack, hopes dim for international Iranian sanctions

Dennis Horak: Attack on Saudi oil refineries may be a chance to move the peace needle

Compiled by Globe staff

Associated Press and Reuters, with reports from The New York Times News Service and Globe staff